Lovejoy would deal with Flanders' concerns very briefly, so that he could return to playing with his model trains. At one point, Lovejoy "just stopped caring",[3] but rediscovered the joy of helping others, though Ned still irritates him.[3] Lovejoy even suggests Ned join another religion, as "they are all pretty much the same". In the season two episode "Homer vs. Lisa and the 8th Commandment", Lovejoy helps Lisa with her family's illegal cable hookup.

His tolerant side is demonstrated when he performs a Hindu marriage ceremony for Kwik-E-Mart shopkeeper Apu[7] (though Lovejoy does not know much about the faith, referring to it in an earlier episode as "Miscellaneous"), co-hosts a religious radio program with Krusty the Klown's rabbi father,[8] and admits evolution may be true. However, Lovejoy can also be intolerant. When Lisa Simpson converted to Buddhism, he referred to her as "Marge Simpson's devil-daughter".[9] He appears bitter about the tall Episcopal church across the street, wanting to build a larger steeple, and when mentioning the other church, placing the emphasis on "pis".[10] He maintains two rolodexes – one for Christians, and one for non-Christians.[11] While he seems to have originally accepted evolution, he later takes up the creationist cause to bolster his church's membership.[12]

He is especially intolerant of the Roman Catholic Church as he is shown brawling with a priest.[13] He tells Marge that he might as well do a Voodoo dance for Abe Simpson when asked to give him the last rites.[14] He also helps kidnap Bart to keep him from converting to Catholicism.[1] Lovejoy, while he claims he's not against the idea of gay people being in a relationship, is opposed to the idea of same-sex marriage,[15] and declared that he could not marry two people of the same sex any more than he could put a hamburger on a hot dog bun.

Lovejoy has been shown to do things that would be considered sinful. Lovejoy has been known to exploit his congregation for money, brawl with a Roman Catholic priest,[13] encourage his pet Old English Sheepdog to foul Ned Flanders's lawn,[16] and implied that he once burned down his church for insurance money.[17] In "Whacking Day", he made up a passage in the Bible to attempt to convince Lisa that "even God himself endorses Whacking Day". In "The Joy of Sect", the episode in which the whole town of Springfield is deceived into joining a cult, Lovejoy kidnaps Homer with Groundskeeper Willie from the cult and hits him across the head numerous times hoping to knock him out. Also, when Lovejoy sees the spaceship emerge from the "forbidden barn" he throws his religious collar on the ground. After it is revealed that the spaceship is fake, Ned Flanders notices his collar on the ground and informs Lovejoy, who picks it up and puts it back on.

Lovejoy is not always enthusiastic about the Bible, calling it a "2000-page sleeping pill".[9] It is unsure if he even owns a Bible, as it was once said he borrows one from the library every week. However, he can exactly quote even obscure passages from memory. In "Secrets of a Successful Marriage," an episode that dealt with marriage counseling, Lovejoy and his gossipy wife, Helen, both recommend that Marge should divorce Homer. Marge objects, pointing out how the Bible has strict guidelines against divorce, but Lovejoy says, "Marge, everything is a sin. (holds up the Bible) Have you ever sat down and read this thing? Technically we're not allowed to go to the bathroom."

Matt Groening has indicated that Lovejoy is named after Lovejoy Street (which in turn is named for Portland co-founder Asa Lovejoy)[19] in Portland, Oregon, the city where Groening grew up.[20][21][22] Lovejoy became the central character in the episode "In Marge We Trust". By season eight, the show had begun to explore secondary characters. Lovejoy was selected for this episode because, aside from being noted as "the priest who didn't care", he had not had much character development.[23]